“The real source of the hypothesis,” said Wheaton, “is the fact that Neanderthals seem to have made no projectile ­weapons. Their spears were useful only for stabbing. And the terrain they lived in didn’t lend itself to open running, the way Erectus hunted. I don’t care how stealthy you are, you can’t sneak close enough to an aurochs to jab it between the ribs. The last distance has to be crossed in a run, and then the Neanderthal had to jump on its back and stab it at the base of the skull, severing the spinal column.”

“And the aurochs held still for this,” said Ram.

“It bucked and ran like a son-of-a-bitch,” said Wheaton. “But Neanderthals are strong. They gripped with their thighs long enough to ram that spear into the spine and bring the beast crashing down.”

“Though Father’s guesswork,” said Deborah, “doesn’t explain how you jump onto a bull’s back over the horns and somehow end up facing forward.”

“They were very agile,” said Wheaton.

“Let’s go find out,” said Noxon. “Perhaps you can get me to a place where you know that aurochses were hunted.”

“Not aurochses,” said Deborah. “ ‘Aurochs’ is singular and plural.”

“But Deborah uses the pseudo-Germanic plural ‘aurochsen’ when she wants to show off,” said Wheaton.

“Like ‘ox’ and ‘oxen,’” she said.

“A place where you know they were eating aurochsoto,” said Noxon, using a plural from the trade language of the Stashi riverlands. “Then I can hunt for paths with a reasonable hope of success.”

The place turned out to be in Slovenia, a tiny nation. But it had one of the better Neanderthal settlement sites, occupied for thousands of years. What Noxon quickly realized was that it was actually occupied six times for a single season each. But there was no way the anthropologists could have seen the discontinuities.

Noxon found paths that seemed to be hunters returning from a large kill—their arrival was followed by a feast and then a lot of meat-smoking—and then sensed where they had acquired their kill. That first attempt was a dead end, though—the hunters had found a dead aurochs, brought down by a combination of dire wolves and disease.

But his second try brought the hunters back to the path of a living aurochs, and Noxon could sense that one Neanderthal’s path did indeed take him onto the aurochs’s back while it was still alive. Then he looked over the map, fitting the paths onto it as best he could. “No roads take us any closer than we already are,” he said. “So we’ve got about ten kilometers of walking to do.”

“How old is the event?” asked Wheaton.

“It’s the oldest group that spent a season here,” said Noxon. “Isn’t there already a date? Carbon 14, at least?”

“The oldest fire built here dates from ninety thousand years ago,” said Wheaton.